Is there a way to add a code in an EA so that it will only work on one pc by locking the EA to the physical MAC address of a computer?
If you would have a Windows system you would be able to use Microsofts WinApi:
But on Mac I have no idea whether there is a similar way.. :(
You can change your mac adress.
You can use Market.
or read the following articles -
Protect Yourselves, Developers! - the article